A Universal Serial Bus (USB) is a serial bus standard to interface devices. The USB was designed to allow peripherals to be connected using a single standardized interface socket and to improve plug-and-play capabilities by allowing devices to be connected and disconnected without rebooting the computer (hot swapping). Other convenient features include providing power to low-consumption devices without the need for an external power supply and allowing many devices to be used without requiring manufacturer specific, individual device drivers to be installed.
USB is intended to help retire all legacy varieties of serial and parallel ports. USB can connect computer peripherals such as mouse devices, keyboards, PDAs, gamepads and joysticks, scanners, digital cameras, printers, personal media players, and flash drives. For many of those devices USB has become the standard connection method. USB is also used extensively to connect non-networked printers; USB simplifies connecting several printers to one computer. As USB technology improves there are a large volume of USB memory devices, including flash memory devices.
USB flash drives are NAND-type flash memory data storage devices integrated with a USB (universal serial bus) connector. They are typically small, lightweight, removable and rewritable. USB Memory card readers are also available, whereby rather than being built-in, the memory is a removable flash memory card housed in what is otherwise a regular USB flash drive.
Although the flash drive comes in a compact packages, standard USB flash memory devices typically have several components. A male USB connector provides an interface to the host computer. A USB mass storage controller implements the USB host controller and provides a linear interface to block-oriented serial flash devices while hiding the complexities of block-orientation, block erasure, and wear levelling, or wear balancing. The controller contains a small RISC microprocessor and a small amount of on-chip ROM and RAM. A NAND flash memory chip stores data. NAND flash is typically also used in digital cameras. A crystal oscillator produces the device's main 12 MHz clock signal and controls the device's data output through a phase-locked loop. Jumpers and test pins for testing during the flash drive's manufacturing or loading code into the microprocessor. LEDs indicate data transfers or data reads and writes. Write-protect switches—indicate whether the device should be in “write-protection”
Another component of the USB flash drive is a USB connector cover or cap. This cap reduces the risk of damage due to static electricity, and improves overall device appearance. Some flash drives do not feature a cap, but instead have retractable USB connectors. Other flash drives have a “swivel” cap that is permanently connected to the drive itself and eliminates the chance of losing the cap.
Although the cap cover provides a main function of protecting the USB connector, the USB is capable of serving additional functions with regard to conveying information on the USB package. Despite the capability to display information on the USB package, there remains a need for USB cover cap that can also be used to display information.